Techniques for fluoroscopic cardiac measurement

ABSTRACT

A method is described, for use with a native valve of a heart of a subject, the valve being disposed between an atrium and a ventricle of the heart. A first radiopaque marker and a second radiopaque marker are percutaneously advanced to the heart. The first radiopaque marker is placed against a tissue site in the ventricle. The second radiopaque marker is placed against a component of the valve. A distance is fluoroscopically measured between the first radiopaque marker at the tissue site, and the second radiopaque marker at the component. At least one of the radiopaque markers is then withdrawn from the heart. Other embodiments are also described.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. Ser. No. 16/926,580 to Reich, filed on Jul. 10, 2020, which published as US 2020/0337840, and which is a continuation of International Patent Application No. PCT/IL2019/050083 to Reich, filed on Jan. 22, 2019, which published as WO 2019/145941, and which claims priority from U.S. Provisional Patent Application 62/622,315 to Reich, filed Jan. 26, 2018, each of which is incorporated herein by reference.

FIELD OF THE INVENTION

Some applications of the present invention relate in general to cardiac repair. More specifically, some applications of the present invention relate to facilitating implantation of artificial chordae tendineae.

BACKGROUND

Ischemic heart disease can cause mitral regurgitation by the combination of ischemic dysfunction of the papillary muscles, and the dilatation of the left ventricle that is present in ischemic heart disease, with the subsequent displacement of the papillary muscles and the dilatation of the mitral valve annulus.

Dilation of the annulus of the mitral valve can prevent the valve leaflets from fully coapting when the valve is closed. Mitral regurgitation of blood from the left ventricle into the left atrium can result in increased total stroke volume and decreased cardiac output, and ultimate weakening of the left ventricle secondary to a volume overload and a pressure overload of the left atrium.

Chronic or acute left ventricular dilatation can lead to papillary muscle displacement with increased leaflet tethering due to tension on chordae tendineae, as well as annular dilatation.

SUMMARY OF THE INVENTION

Techniques are provided for determining an appropriate chord-length for an artificial chorda tendinea by placing markers, such as radiopaque markers, against tissue sites within the heart, and calculating (e.g., measuring, calculating using a computer program, etc.) a distance between the markers. Typically, one marker is placed against a papillary muscle, and another marker is placed against one or more leaflets, and the chord-length is based on the calculated or measured distance between these markers. The artificial chorda tendinea can then be implanted.

The determination of the chord-length and the implantation of the artificial chorda tendinea are typically performed percutaneously, e.g., transluminally (i.e., via a blood vessel), such as transfemorally, transseptally, etc. Therefore, the techniques described herein can be performed without line-of-sight or direct visualization, but instead can be facilitated by imaging technologies such as echocardiography and fluoroscopy.

There is therefore provided, in an exemplary application, a method for use in a heart (e.g., for use with a native valve of a heart of a subject). The method includes percutaneously advancing a first radiopaque marker and a second radiopaque marker to the heart. The method also includes placing the first radiopaque marker against a first tissue site in the heart (e.g., the ventricle) and placing the second radiopaque marker at a second tissue site in the heart (e.g., at or proximate a valve of the heart, such as an atrioventricular valve, etc.). The method also includes calculating and/or measuring a distance between the first radiopaque marker at the first tissue site, and the second radiopaque marker at the second tissue site, and responsively to the distance (i.e., the distance calculated or measured), determining a tether-length.

Placing the second radiopaque marker against the leaflet can include placing the second radiopaque marker against a free edge of the leaflet. Placing the first radiopaque marker against the first tissue site can include anchoring, to the first tissue site, an anchor that includes the first radiopaque marker. Placing the first radiopaque marker against the first tissue site can include placing the first radiopaque marker against the first tissue site under echocardiographic guidance. Placing the second radiopaque marker against the second tissue site can include placing the second radiopaque marker against the second tissue site under echocardiographic guidance.

Calculating or measuring the distance can include measuring the distance using fluoroscopy and/or on a fluoroscopic image. Calculating or measuring the distance can include using a computer program or software to measure and/or estimate the distance between markers. The computer program or software can use image recognition and/or other tools, sensors, inputs, etc. to measure and/or estimate the distance between markers.

Advancing the first and second radiopaque markers can include advancing the first and second radiopaque markers transluminally (e.g., transfemorally, transseptally, etc.).

The second tissue site can be a first leaflet of a valve of the heart, and placing the first radiopaque marker against the second tissue site can include placing the first radiopaque marker at a systolic coaptation level between the first leaflet and a second leaflet of the valve.

The first tissue site can be on a papillary muscle, and placing the first radiopaque marker against the first tissue site can include placing the first radiopaque marker against the papillary muscle.

The method can further include selecting the tether based on and/or having the tether-length from a selection of tethers that includes at least one tether that does not have the tether-length (e.g., being longer than the tether-length). The method can include adjusting the tether to the tether-length. For example, the method can include trimming the tether to the tether-length.

The method can further include implanting, in the heart, a tether selected based on and/or having the tether-length.

Implanting the tether can include attaching a first end portion of the tether to the tissue site and attaching a second end portion of the tether to the second tissue site.

The method can also include additional steps described elsewhere in this disclosure.

In an exemplary application, a method for use with a native valve of a heart of a subject (the valve can be disposed between an atrium and a ventricle of the heart) the method including:

percutaneously advancing a first radiopaque marker and a second radiopaque marker to the heart;

placing the first radiopaque marker against a tissue site in the ventricle;

placing the second radiopaque marker against a leaflet of the valve;

calculating or measuring a distance between the first radiopaque marker at the tissue site, and the second radiopaque marker at the leaflet; and

responsively to the distance (i.e., the calculated or measured distance), determining a chord-length.

In an application, placing the first radiopaque marker against the tissue site includes anchoring, to the tissue site, a tissue anchor that includes the first radiopaque marker.

In an application, placing the first radiopaque marker against the tissue site includes placing the first radiopaque marker against the tissue site under echocardiographic guidance.

In an application, placing the second radiopaque marker against the leaflet includes placing the first radiopaque marker against the leaflet under echocardiographic guidance.

In an application, calculating or measuring the distance includes measuring the distance using fluoroscopy and/or measuring the distance on a fluoroscopic image. Calculating or measuring the distance can include using a computer program or software to measure and/or estimate the distance between markers. The computer program or software can use image recognition and/or other tools, sensors, inputs, etc. to measure and/or estimate the distance between markers.

In an application, advancing the first and second radiopaque markers includes advancing the first and second radiopaque markers transluminally.

In an application, the leaflet is a first leaflet, and placing the first radiopaque marker against the leaflet includes placing the first radiopaque marker at a systolic coaptation level between the first leaflet and a second leaflet of the valve.

In an application, the tissue site is on a papillary muscle, and placing the first radiopaque marker against the tissue site includes placing the first radiopaque marker against the papillary muscle.

In an application, the method further includes selecting the artificial chord based on and/or having the chord-length from a selection of chords that includes at least one chord that does not have the chord-length.

In an application, the method further includes adjusting the artificial chord to the chord-length.

In an application, the method further includes trimming the artificial chord to the chord-length.

The method can further include implanting, in the heart, an artificial chord based on and/or having the chord-length.

In an application, implanting the artificial chord includes attaching a first end portion of the artificial chord to the tissue site and attaching a second end portion of the artificial chord to the leaflet.

In an application:

the leaflet is a first leaflet,

the artificial chord is a first artificial chord,

implanting the artificial chord includes attaching a first end portion of the first artificial chord to the tissue site and attaching a second end portion of the first artificial chord to the leaflet, and

the method further includes implanting a second artificial chord by attaching a second end portion of the second artificial chord to a second leaflet of the native valve.

In an application, implanting the second artificial chord includes attaching a first end portion of the second artificial chord to a second tissue site in the ventricle.

In an application, the first radiopaque marker is disposed on a first elongate tool, and placing the first radiopaque marker against the tissue site includes placing the first tool against the tissue site.

In an application, the first tool is shaped to define a lumen therethrough, and the method further includes advancing the artificial chord to the heart within the lumen.

In an application, implanting the artificial chord includes anchoring a first end portion of the artificial chord to the tissue site without removing the first tool from the tissue site.

In an application, implanting the artificial chord includes anchoring a tissue anchor to the tissue site without removing the first tool from the tissue site.

In an application, a first end portion of the artificial chord is attached to the tissue anchor, and anchoring the tissue anchor to the tissue site includes anchoring the first end portion of the artificial chord to the tissue site.

In an application, an elongate guide member is coupled to the tissue anchor, and anchoring the tissue anchor to the tissue site includes anchoring the guide member to the tissue site.

In an application, implanting the artificial chord includes, subsequently to anchoring the tissue anchor, advancing the artificial chord along the guide member to the tissue anchor and coupling the artificial chord to the tissue anchor.

In an application, the method further includes, subsequently to anchoring the tissue anchor, removing the first tool from the tissue site and the tissue anchor, and advancing the artificial chord along the guide member to the tissue anchor includes advancing the artificial chord along the guide member to the tissue anchor subsequently to removing the first tool from the tissue site and the tissue anchor.

In an application, the method further includes, subsequently to coupling the artificial chord to the tissue anchor, decoupling the guide member from the tissue anchor.

In an application, the first radiopaque marker is disposed on a distal end of the first tool, and placing the first radiopaque marker against the tissue site includes placing the distal end of the first tool against the tissue site.

In an application, the first radiopaque marker is disposed on a first elongate tool, the second radiopaque marker is disposed on a second elongate tool that is slidably coupled to the first tool, and:

advancing the first radiopaque marker and the second radiopaque marker to the heart includes advancing the first tool and the second tool to the heart, and

the method further includes sliding the second tool with respect to the first tool in order to place at least one radiopaque marker selected from the group consisting of: the first radiopaque marker and the second radiopaque marker.

In an application:

the second tool includes a longitudinal shaft and an appendage,

the second radiopaque marker is disposed on the appendage,

the method further includes extending the appendage laterally from the longitudinal shaft, and

placing the second radiopaque marker against the leaflet includes moving the second tool until the appendage abuts the leaflet.

In an application, the first tool is slidable within the second tool, and sliding the second tool with respect to the first tool includes sliding the first tool within the second tool.

There is further provided, in an exemplary application, a method, including:

advancing a first marker (e.g., a first radiopaque marker) and a second marker (e.g., a second radiopaque marker) along a simulated vasculature to a simulated heart, the heart having a simulated valve disposed between a simulated atrium and a simulated ventricle;

placing the first marker against a simulated tissue site in the ventricle;

placing the second marker against a simulated leaflet of the valve;

calculating or measuring a distance between the first marker at the tissue site, and the second marker at the leaflet; and

responsively to the distance, determining a chord-length.

The simulated vasculature can be a computer-simulated vasculature, the simulated heart can be a computer-simulated heart, and the step of advancing can include advancing the first marker and the second marker along the computer-simulated vasculature to the computer-simulated heart.

The simulated vasculature can be a physical model of vasculature, the simulated heart can be a physical model of a heart, and the step of advancing can include advancing the first marker and the second marker along the physical model of the vasculature to the physical model of the heart.

The markers can be radiopaque markers, computer-simulated markers, or computer-simulated radiopaque markers.

In an application, calculating or measuring the distance includes measuring the distance using fluoroscopy and/or measuring the distance on a fluoroscopic image. Calculating or measuring the distance can include using a computer program or software to measure and/or estimate the distance between markers. The computer program or software can use image recognition and/or other tools, sensors, inputs, etc. to measure and/or estimate the distance between markers.

In some applications, the first marker is a first computer-simulated radiopaque marker and the second marker is a second computer-simulated radiopaque marker, and calculating the distance comprises measuring the distance between the first computer-simulated radiopaque marker and the second computer-simulated radiopaque marker on a computer-simulated fluoroscopic image.

The simulated heart can be a simulation of a heart of a particular human subject, and the method can be a method for planning a chord-implantation procedure on the particular human subject.

In an application, placing the first marker against the tissue site includes anchoring, to the tissue site, a tissue anchor that includes the first marker.

In an application, placing the first marker against the tissue site includes placing the first marker against the tissue site under echocardiographic guidance.

In an application, placing the second marker against the leaflet includes placing the first marker against the leaflet under echocardiographic guidance.

The echocardiographic guidance can use actual ultrasound, or can be computer-simulated.

In an application, calculating or measuring the distance includes measuring the distance using fluoroscopy.

The fluoroscopy can be actual fluoroscopy, or can be computer-simulated fluoroscopy.

In an application, the leaflet is a first simulated leaflet, and placing the first marker against the leaflet includes placing the first marker at a coaptation level between the first leaflet and a second simulated leaflet of the valve.

In an application, the tissue site is on a simulated papillary muscle, and placing the first marker against the tissue site includes placing the first marker against the papillary muscle.

In an application, the method further includes selecting the artificial chord based on the chord-length from a selection of chords that includes at least one chord that does not have the chord-length.

In an application, the method further includes adjusting the artificial chord to the chord-length.

In an application, the method further includes trimming the artificial chord to the chord-length.

In an application, the method further includes implanting, in the heart, an artificial chord selected based on the chord-length.

In an application, implanting the artificial chord includes attaching a first end portion of the artificial chord to the tissue site and attaching a second end portion of the artificial chord to the leaflet.

In an application:

the leaflet is a first simulated leaflet,

the artificial chord is a first artificial chord,

implanting the artificial chord includes attaching a first end portion of the first artificial chord to the tissue site and attaching a second end portion of the first artificial chord to the first simulated leaflet, and

the method further includes implanting a second artificial chord by attaching a second end portion of the second artificial chord to a second simulated leaflet of the simulated valve.

In an application, implanting the second artificial chord includes attaching a first end portion of the second artificial chord to a second simulated tissue site in the ventricle.

In an application, the first marker is disposed on a first elongate tool, and placing the first marker against the tissue site includes placing the first tool against the tissue site.

In an application, the first tool is shaped to define a lumen therethrough, and the method further includes advancing the artificial chord to the heart within the lumen.

In an application, implanting the artificial chord includes anchoring a first end portion of the artificial chord to the tissue site without removing the first tool from the tis sue site.

In an application, implanting the artificial chord includes anchoring a tissue anchor to the tissue site without removing the first tool from the tissue site.

In an application, a first end portion of the artificial chord is attached to the tis sue anchor, and anchoring the tissue anchor to the tissue site includes anchoring the first end portion of the artificial chord to the tissue site.

In an application, an elongate guide member is coupled to the tissue anchor, and anchoring the tissue anchor to the tissue site includes anchoring the guide member to the tissue site.

In an application, implanting the artificial chord includes, subsequently to anchoring the tissue anchor, advancing the artificial chord along the guide member to the tissue anchor and coupling the artificial chord to the tissue anchor.

In an application, the method further includes, subsequently to anchoring the tissue anchor, removing the first tool from the tissue site and the tissue anchor, and advancing the artificial chord along the guide member to the tissue anchor includes advancing the artificial chord along the guide member to the tissue anchor subsequently to removing the first tool from the tissue site and the tissue anchor.

In an application, the method further includes, subsequently to coupling the artificial chord to the tissue anchor, decoupling the guide member from the tissue anchor.

In an application, the first marker is disposed on a distal end of the first tool, and placing the first marker against the tissue site includes placing the distal end of the first tool against the tissue site.

In an application, the first marker is disposed on a first elongate tool, the second marker is disposed on a second elongate tool that is slidably coupled to the first tool, and:

advancing the first marker and the second marker to the heart includes advancing the first tool and the second tool to the heart, and

the method further includes sliding the second tool with respect to the first tool in order to place at least one radiopaque marker selected from the group consisting of: the first marker and the second marker.

In an application:

the second tool includes a longitudinal shaft and an appendage,

the second marker is disposed on the appendage,

the method further includes extending the appendage laterally from the longitudinal shaft, and

placing the second marker against the leaflet includes moving the second tool until the appendage abuts the leaflet.

In an application, the first tool is slidable within the second tool, and sliding the second tool with respect to the first tool includes sliding the first tool within the second tool.

There is further provided, in accordance with an application of the present invention, a method, including:

advancing a first marker (e.g., first radiopaque marker) and a second marker (e.g., second radiopaque marker) along a simulated vasculature to a simulated heart, the heart having a simulated valve disposed between a simulated atrium and a simulated ventricle;

placing the first marker against a first simulated tissue site in the ventricle;

placing the second marker at a second simulated tissue site at or proximate the valve;

calculating or measuring a distance between the first marker at the first tissue site, and the second marker at the second tissue site; and

responsively to the distance, determining a tether-length.

In an application:

the simulated vasculature is a computer-simulated vasculature, and the simulated heart is a computer-simulated heart; and

the step of advancing includes advancing the first marker and the second marker along the computer-simulated vasculature to the computer-simulated heart.

In an application:

the simulated vasculature is a physical model of vasculature, and the simulated heart is a physical model of a heart; and

the step of advancing includes advancing the first marker and the second marker along the physical model of the vasculature to the physical model of the heart.

In an application:

the simulated heart is a simulation of a heart of a particular human subject, and

the method is a method for planning a tether-implantation procedure on the particular human subject.

In an application, placing the first marker against the first tissue site includes anchoring, to the first tissue site, an anchor that includes the first marker.

In an application, placing the first marker against the first tissue site includes placing the first marker against the first tissue site under echocardiographic guidance.

In an application, placing the second marker against the second tissue site includes placing the second marker against the second tissue site under echocardiographic guidance.

In an application, calculating or measuring the distance includes measuring the distance using fluoroscopy and/or measuring the distance on a fluoroscopic image. Calculating or measuring the distance can include using a computer program or software to measure and/or estimate the distance between markers. The computer program or software can use image recognition and/or other tools, sensors, inputs, etc. to measure and/or estimate the distance between markers.

In an application, the second tissue site is a first simulated leaflet, and placing the first marker against the second tissue site includes placing the first marker at a systolic coaptation level between the first leaflet and a second simulated leaflet of the valve.

In an application, the first tissue site is on a simulated papillary muscle, and placing the first marker against the first tissue site includes placing the first marker against the papillary muscle.

In an application, the method further includes selecting the tether based on the tether-length from a selection of tethers that includes at least one tether that does not have the tether-length.

In an application, the method further includes adjusting the tether to the tether-length.

In an application, the method further includes trimming the tether to the tether-length.

In an application, the method further includes implanting, in the heart, a tether selected based on the tether-length.

In an application, implanting the tether includes attaching a first end portion of the tether to the tissue site and attaching a second end portion of the tether to the second tissue site.

The present invention will be more fully understood from the following detailed description of applications thereof, taken together with the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-F are schematic illustrations showing a technique for use with a native valve of a heart of a subject, in accordance with some applications of the invention;

FIGS. 2A-B are schematic illustrations showing an alternative technique for use with the native valve, in accordance with some applications of the invention; and

FIG. 3 is a schematic illustration showing another alternative technique for use with the native valve, in accordance with some applications of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is made to FIGS. 1A-F, which are schematic illustrations showing a technique for use with a native valve 10 of a heart 4 of a subject, in accordance with some applications of the invention. Valve 10 is an atrioventricular valve, disposed between an atrium and a ventricle of the heart. For example, and as shown, valve 10 may be a mitral valve, disposed between left atrium 6 and left ventricle 8 of the heart. Valve 10 could also be a tricuspid valve. Any and all of the methods, techniques, steps, etc. described herein can be performed on a living animal or on a non-living cadaver, cadaver heart, simulator, anthropomorphic ghost, etc.

A first marker or first radiopaque marker 32 and a second marker or a second radiopaque marker 34 are advanced to the heart. Marker 32 can be disposed on (e.g., at a distal end of) a first tool 22. Marker 34 can be disposed on (e.g., at a distal end of) a second tool 24. It is to be noted that, in this context, the terms “first” and “second” are used purely to distinguish each marker from the other, and each tool from the other, and are not intended to specify an order in which these elements are arranged or used.

First marker 32 is placed against a tissue site 42 in ventricle 8 (FIG. 1A). For example, first tool 22 may be advanced into the ventricle until the distal end of the tool is disposed against tissue site 42 (e.g., a papillary muscle, heart wall, ventricular wall, septum, apex, etc.). As shown, this may be performed transluminally (e.g., transfemorally, transseptally, etc.) or transapically. In one application, a sheath 20 can be advanced transfemorally/transseptally to the heart, and tools 22 and 24 can be advanced via the sheath.

For some applications, and as shown, tissue site 42 is on a papillary muscle 12 of the heart. For some applications, tissue site 42 is on a ventricular wall (e.g., inner wall, septum, outer wall, etc.) of the heart.

For some applications, second marker 34 is placed against a tissue site 44 in the atrium, ventricle, or between, e.g., on one or multiple leaflets 14 of valve 10 (FIGS. 1B-C). For example, second tool 24 can be advanced into the ventricle until the distal end of the tool is disposed against tissue site 44. This can be performed transluminally (e.g., transfemorally, transseptally, etc.). For some applications, marker 34 is placed against an upstream surface of leaflet 14. For some applications, marker 34 is placed at a level of systolic coaptation between two leaflets 14. For some applications, marker 34 is placed at the free edge of one or more of the leaflets. It is to be noted that the term “level of systolic coaptation” (including the specification and the claims) means the level (e.g., on the long axis of the heart) at which leaflets 14 coapt during ventricular systole. For such applications, if valve 10 suffers from leaflet flail, the level of systolic coaptation is typically the level at which the coapting regions of the leaflets coapt.

For some applications, tool 22 is slidably coupled to tool 24, such that the operator slides the tools with respect to each other in order to place markers 32 and 34 against their corresponding tissue sites. For example, tool 22 can be slidable within tool 24 (e.g., coaxially, as shown), or tool 24 can be slidable within tool 22. Tools 22 and 24 could also be slidable or otherwise movable adjacent to each other without necessarily being coaxial or one inside the other.

For some applications, second tool 24 includes a longitudinal shaft 26 and marker 34 is disposed on the longitudinal shaft. For some applications, and as shown in FIG. 1C, second tool 24 comprises a longitudinal shaft 26, and an appendage 28 on which marker 34 is disposed. For such applications, marker 34 is typically placed against tissue site 44, e.g., by moving tool 24 until the marker and/or appendage 28 abuts the leaflets. Appendage 28 can be laterally extendible (e.g., radially expandable) from shaft 26. For such applications, appendage 28 can be laterally extended from shaft 26 in order to provide a wide span for abutting leaflet(s) 14. For example, shaft 26 can have a lateral width of 2-10 mm, whereas appendage 28, when extended (e.g., when in an expanded state), can have a span of 6-15 mm. Alternatively or additionally, the span of appendage 28 when extended can be 0.5-5 mm (e.g., 2-5 mm, such as 3-5 mm) greater than the lateral width of shaft 26.

For some applications, appendage 28 is self-expanding, and is transitioned into its expanded state by exposing it from shaft 26. For example, appendage 28 can comprise an elastic and/or shape memory material such as Nitinol. For some applications, appendage 28 has a stent structure. For some applications, appendage 28 has a braid structure. For some applications, appendage 28 is mechanically expanded, e.g., using an actuator. For some applications, appendage 28 is expanded using a balloon.

For some applications, one or more imaging techniques (e.g., echocardiographic and/or fluoroscopic guidance) are used to facilitate placement of marker 32 and/or marker 34. For example, although for some applications abutment of appendage 28 against leaflets 14 can be detected via tactile feedback, this abutment can be alternatively or additionally determined using one or more imaging techniques.

A distance dl can be calculated or measured between the marker 32 at tissue site 42, and marker 34 at tissue site 44. The distance can be measured by observing markers 32 and 42 using fluoroscopy (e.g., determining dl from measurement of the distance between markers on a fluoroscopy image), and/or by judging the relative insertion distance of tools 22 and 24 (e.g., a proximal end remaining outside the body can include markings or gradations to show relative distance between the tools and their markers when the markers are positioned as desired). It is hypothesized by the inventor that fluoroscopy provides a more accurate indication and/or measurement of distance dl than do other techniques, such as echocardiography.

Responsively to measured distance dl, an appropriate chord-length is determined for an artificial chord (i.e., an artificial chorda tendinea) or other tether or line to be implanted in the heart. For some applications, the chord/tether-length can be equal to distance dl. For some applications, the chord/tether-length can be greater than distance dl. For some applications, the chord/tether-length can be smaller than distance dl.

An artificial chord 60 or other tether/line (discussion of chord 60 also applies to other tethers/lines that can serve other functions and/or be positioned differently from an artificial chorda tendinea), having the determined chord/tether-length, is subsequently implanted in the heart. For some applications, chord/tether 60 is selected from a selection of chords/tethers that includes at least one chord/tether that does not have the determined chord/tether-length. For some applications, chord/tether 60 is adjusted to the determined chord/tether-length. For some applications, chord/tether 60 is trimmed to the determined chord/tether-length.

FIGS. 1D-F show implantation of chord/tether 60, in accordance with some applications of the invention. Chord/60 is attached to tissue sites 42 and 44. That is, a first end portion of chord/tether 60 is attached to site 42 (FIG. 1D), and a second end portion of the chord/tether is attached to site 44 (FIG. 1F). These end portions can be attached in a variety of different ways.

For some applications, tool 22 is shaped to define a lumen therethrough, and chord/tether 60 is advanced to the heart within the lumen. For such applications, the attachment of the first end portion of chord/tether 60 to tissue site 42 is typically performed without removing tool 22 from the tissue site. That is, for such applications, tool 22 can remain at the same tissue site 42 as when distance dl was measured, at least until the first end portion of chord/tether 60 is attached to tissue site 42.

For some applications, and as shown, a tissue anchor 62 is attached to tissue site 42 in order to facilitate attachment of chord/tether 60 to the tissue site. However, other types of attachment means can be used, e.g., clips, sutures, adhesives, knots, pledgets, staples, other anchors, etc.

For some applications in which tissue anchor 62 is used, the first end portion of chord/tether 60 is attached to the tissue anchor (i.e., the chord/tether is provided with the anchor pre-attached), and anchoring the tissue anchor to tissue site 42 anchors the first end portion of chord to the tissue site. FIG. 1E shows tool 50 being withdrawn after anchoring tissue anchor 62 to tissue site 42, with chord/tether 60 extending proximally from the tissue anchor.

FIG. 1F shows the second end-portion of chord/tether 60 having been attached to tissue site 44, or in this example, a leaflet 14. This attachment may be performed before or after the attachment of the first end-portion of chord/tether 60 to tissue site 42. For some applications, and as shown, chord/tether 60 can have a clip 64 pre-attached to the second end-portion of the chord, and clipping the clip to leaflet 14 attaches the second end-portion of the chord/tether to the leaflet. It is to be noted that the attachment of chord/tether 60 to site 44 or leaflet 14 can be implemented alternatively or additionally using other techniques, such as with other attachment means described herein and/or technology described, mutatis mutandis, in one or more of the following publications, which are incorporated herein by reference:

U.S. Pat. No. 8,690,939 to Miller et al.

U.S. Pat. No. 8,734,467 to Miller et al.

U.S. Pat. No. 9,277,994 to Miller et al.

Reference is now made to FIGS. 2A-B, which are schematic illustration showing an optional technique for use with native valve 10, in accordance with some applications. The technique shown in FIGS. 2A-B is typically the same as that of FIGS. 1A-F, mutatis mutandis, except that instead of tissue anchor 62 being provided pre-attached to chord/tether 60, the anchor is coupled to an elongate guide member 70 (i.e., the anchor is implanted with the guide member pre-coupled). Anchoring tissue anchor 62 to tissue site 42 anchors guide member 70 to the tissue site. FIG. 2A shows tool 50 having been withdrawn after anchoring tissue anchor 62 to tissue site 42, with guide member 70 extending proximally from the tissue anchor. Subsequently, artificial chord 60 is advanced along guide member 70 (e.g., within tool 22, or after tool 22 has been withdrawn) to tissue anchor 62, and is coupled to the tissue anchor (FIG. 2B). For example, and as shown, a distal end of chord 60 can be attached to a coupling 61 that is configured (e.g., shaped) to lock onto a proximal portion (e.g., a head) of anchor 62. For such applications, guide member 70 is typically subsequently decoupled from anchor 62, and removed from the subject. For some such applications, tool 22 is removed from tissue site 42 (e.g., from the heart entirely) after anchor 62 is anchored, and before chord/tether 60 is advanced along guide member 70 to tissue anchor 62.

For some applications, coupling of chord/tether 60 to tissue anchor 62 can be implemented using attachment means herein or technology described, mutatis mutandis, in one or more of the following publications, which are incorporated herein by reference:

U.S. Pat. No. 8,690,939 to Miller et al.

U.S. Pat. No. 8,734,467 to Miller et al.

U.S. Pat. No. 9,277,994 to Miller et al.

Reference is now made to FIG. 3 , which is a schematic illustration showing an optional technique for use with native valve 10, in accordance with some applications. For some applications, tissue anchor 62 comprises or is coupled to first radiopaque marker 32. FIG. 3 shows marker 32 as a distinct component of anchor 62, but it is to be understood that anchor 62 may simply be constructed from a radiopaque material, and thereby serve as marker 32. For such applications, tool 22 may not be used.

FIG. 3 shows the technique described with reference to FIGS. 2A-B having been modified using a radiopaque marker 32 that is a component of or is coupled to anchor 62. The technique described with reference to FIGS. 1A-F can be modified in a similar way, mutatis mutandis. For example, after anchor 62 has been anchored to site 42 (e.g., papillary muscle 12), the distance between markers 32 and 34 is measured, in order to determine the chord/tether-length.

Reference is again made to FIGS. 1A-F, 2A-B, and 3. For some applications, more than one artificial chord or tether is implanted, facilitated by the techniques described hereinabove. For example, a second artificial chord can be attached to a second leaflet 14. For some applications, the second artificial chord can be attached to another ventricular tissue site, e.g., on another papillary muscle or other site. Optionally, the second artificial chord can be attached to the same tissue site 42, e.g., by being attached to the same tissue anchor 62.

Reference is again made to FIGS. 1A-F, 2A-B, and 3. For some applications, the techniques described herein are facilitated by administration of a contrast agent. Although it is hypothesized by the inventor that the techniques described herein provide advantages beyond those provided by contrast agent alone, it is also hypothesized by the inventor that the use of contrast agent may facilitate optimal placement of markers 32 and 34. It is further hypothesized by the inventor that the use of the techniques described herein may advantageously facilitate reduction of the total amount of contrast agent used throughout the procedure.

Reference is again made to FIGS. 1A-F, 2A-B, and 3. The techniques described hereinabove can alternatively or additionally be used with a simulated heart and/or simulated vasculature, e.g., for the purpose of training, and/or for the purpose of planning a procedure on a particular patient. The simulated heart and/or the simulated vasculature may be physical models, e.g., manufactured models, molded models, and/or cadaver models (full cadaver, partial cadaver, and/or cadaver heart), and can be of generalized anatomy or of patient-specific anatomy. Alternatively or additionally, the simulated heart and/or the simulated vasculature can be computer-simulated. With any of these, physical, computer, etc., the simulated techniques can be performed using the same apparatuses, devices, and/or systems as would be used for treating a real subject, mutatis mutandis. Monitors can be used to visualize the procedure and information related to the procedure, e.g., with computers or processors providing input to cause the monitors to display the relevant images and information.

Components, aspects, features, etc. of the systems, apparatuses, devices, methods, etc. described herein can be implemented in hardware, software, or a combination of both. Where components, aspects, features, etc. of the systems, devices, methods, etc. described herein are implemented in software, the software can be stored in an executable format on one or more non-transitory machine-readable mediums. Further, the software and related steps of the methods described above can be implemented in software as a set of data and instructions. Information representing the apparatuses, units, systems, and/or methods stored on the machine-readable medium can be used in the process of creating the apparatuses, units, systems, and/or methods described herein. Hardware used to implement the invention can include integrated circuits, microprocessors, FPGAs, digital signal controllers, stream processors, and/or other components.

The present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features and steps described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description. 

1. A method, comprising: advancing a first radiopaque marker and a second radiopaque marker through vasculature to a heart, the heart having a native valve disposed between an atrium and a ventricle; placing the first radiopaque marker against a tissue site in the ventricle; placing the second radiopaque marker against a component of the native valve; fluoroscopically measuring a distance between the first radiopaque marker at the tissue site, and the second radiopaque marker at the component; and withdrawing from the heart at least one marker selected from the group consisting of: the first radiopaque marker, and the second radiopaque marker.
 2. The method according to claim 1, wherein the selected marker is the second radiopaque marker, and wherein the step of withdrawing comprises withdrawing the second radiopaque marker from the heart.
 3. The method according to claim 1, wherein the selected marker is the first radiopaque marker, and wherein the step of withdrawing comprises withdrawing the first radiopaque marker from the heart.
 4. The method according to claim 1, wherein the step of withdrawing comprises withdrawing the first radiopaque marker and the second radiopaque marker from the heart.
 5. The method according to claim 1, wherein: the vasculature is a physical model of vasculature, and the heart is a physical model of a heart; and the step of advancing comprises advancing the first radiopaque marker and the second radiopaque marker along the physical model of the vasculature to the physical model of the heart.
 6. The method according to claim 1, wherein: the heart is a simulation of a heart of a particular human subject, and the method is a method for planning a chord-implantation procedure on the particular human subject.
 7. The method according to claim 1, wherein: placing the first radiopaque marker against the tissue site comprises anchoring, to the tissue site, a tissue anchor that includes the first radiopaque marker; and the step of withdrawing comprises withdrawing the second radiopaque marker from the heart.
 8. The method according to claim 1, wherein placing the first radiopaque marker against the tissue site comprises placing the first radiopaque marker against the tissue site under echocardiographic guidance, wherein placing the second radiopaque marker against the component comprises placing the second radiopaque marker against the component under echocardiographic guidance, and wherein measuring the distance comprises measuring the distance using fluoroscopy.
 9. The method according to claim 1, wherein the component is a first leaflet of the valve, and wherein placing the second radiopaque marker against the component comprises placing the second radiopaque marker at a coaptation level between the first leaflet and a second leaflet of the valve.
 10. The method according to claim 1, wherein the tissue site is on a papillary muscle, and wherein placing the first radiopaque marker against the tissue site comprises placing the first radiopaque marker against the papillary muscle.
 11. The method according to claim 1, further comprising, determining a chord-length responsively to the measured distance.
 12. The method according to claim 11, further comprising, based on the chord-length, selecting an artificial chord from a selection of chords that includes at least one chord that does not have the chord-length.
 13. The method according to claim 11, further comprising, based on the chord length, adjusting an artificial chord to the chord-length.
 14. The method according to claim 11, further comprising, responsively to the chord-length, implanting an artificial chord in the heart, wherein implanting the artificial chord comprises attaching a first end portion of the artificial chord to the tissue site and attaching a second end portion of the artificial chord to the component of the native valve.
 15. The method according to claim 14, wherein: the component is a first leaflet of the native valve, the artificial chord is a first artificial chord, implanting the artificial chord comprises attaching a first end portion of the first artificial chord to the tissue site and attaching a second end portion of the first artificial chord to the first leaflet, and the method further comprises implanting a second artificial chord by attaching a second end portion of the second artificial chord to a second leaflet of the native valve.
 16. The method according to claim 15, wherein implanting the second artificial chord comprises attaching a first end portion of the second artificial chord to a second tissue site in the ventricle.
 17. The method according to claim 14, wherein the first radiopaque marker is disposed on a first elongate tool and placing the first radiopaque marker against the tissue site comprises placing the first tool against the tissue site.
 18. The method according to claim 17, wherein implanting the artificial chord comprises anchoring a tissue anchor to the tissue site without removing the first elongate tool from the tissue site.
 19. The method according to claim 18, wherein a first end portion of the artificial chord is attached to the tissue anchor, and anchoring the tissue anchor to the tissue site comprises anchoring the first end portion of the artificial chord to the tissue site.
 20. The method according to claim 18, wherein an elongate guide member is coupled to the tissue anchor, and anchoring the tissue anchor to the tissue site comprises anchoring the guide member to the tissue site.
 21. The method according to claim 20, wherein implanting the artificial chord comprises, subsequently to anchoring the tissue anchor, advancing the artificial chord along the guide member to the tissue anchor and coupling the artificial chord to the tissue anchor.
 22. The method according to claim 21, further comprising, subsequently to anchoring the tissue anchor, removing the first tool from the tissue site and the tissue anchor, wherein advancing the artificial chord along the guide member to the tissue anchor comprises advancing the artificial chord along the guide member to the tissue anchor subsequently to removing the first tool from the tissue site and the tissue anchor.
 23. The method according to claim 1, wherein the first radiopaque marker is disposed on a first elongate tool, the second radiopaque marker is disposed on a second elongate tool that is slidably coupled to the first tool, and wherein: advancing the first radiopaque marker and the second radiopaque marker to the heart comprises advancing the first tool and the second tool to the heart, and the method further comprises sliding the second tool with respect to the first tool in order to place at least one radiopaque marker selected from the group consisting of: the first radiopaque marker and the second radiopaque marker.
 24. A method, comprising: advancing a first radiopaque marker and a second radiopaque marker along simulated vasculature to a simulated heart, the simulated heart having a simulated valve disposed between a simulated atrium and a simulated ventricle; placing the first radiopaque marker against a site in the simulated ventricle; placing the second radiopaque marker against a component of the simulated valve; fluoroscopically measuring a distance between the first radiopaque marker at the site, and the second radiopaque marker at the component; and withdrawing from the simulated heart at least one marker selected from the group consisting of: the first radiopaque marker, and the second radiopaque marker. 